CN110650891B

CN110650891B - Positioning unit and attachment unit for container elements

Info

Publication number: CN110650891B
Application number: CN201880033659.3A
Authority: CN
Inventors: S·霍尔卡; P·哈格尔克维斯特
Original assignee: A&R Carton Lund AB
Current assignee: GPI Systems AB
Priority date: 2017-05-23
Filing date: 2018-05-22
Publication date: 2021-07-27
Anticipated expiration: 2038-05-22
Also published as: US11292625B2; WO2018217156A1; CN110650891A; US20200180797A1; ES2913754T3; PL3630617T3; SE1750636A1; EP3630617A4; SE541213C2; EP3630617A1; EP3630617B1

Abstract

The present disclosure relates to a positioning unit (27) for positioning a container element (115, 117, 121, 123, 127) in a container body (103). The positioning unit comprises a base plate (49) of rigid material and a plunger skirt (51) of elastically deformable material. The footprint surface (53) of the substrate has a circumferential edge with a side edge portion comprising an inwardly curved section. The plunger skirt is transitionable between a non-expanded state and an expanded state by relative movement with respect to the base plate. An outer circumference of the plunger skirt has a shape corresponding to the shape of the circumferential edge of the footprint surface of the baseplate, wherein at least one side includes an inwardly curved section. The present disclosure also relates to an attachment unit (5) for attaching a container element to a container body (103), and to an apparatus (1) for attaching a container element to a container body in a flow of containers (101). Furthermore, the present disclosure relates to a method for positioning a container element in a container body by means of said positioning unit.

Description

Positioning unit and attachment unit for container elements

Technical Field

The present disclosure relates to a positioning unit for positioning a container element in a container body. The present disclosure also relates to an attachment unit for attaching a container element to a container body, and to an apparatus for attaching a container element to a container body in a flow of containers. Furthermore, the present disclosure relates to a method of positioning a container element in a container body by means of an attachment unit.

Background

When packaging consumer products, and in particular when packaging dry flowable consumer products, rigid cardboard packaging containers are commonly used, which serve as protective shipping and storage containers at the retail end and storage and dispensing containers at the consumer end. Such paperboard containers are typically provided with an openable and closable lid.

European patent publication EP 247986B 1 discloses an expandable lid welded piston comprising two piston parts; a shaping portion and a dilating portion axially movable relative to each other. The expansion portion is operable to provide circumferential expansion of the section of the piston when the two portions are moved together, the expansion portion including an expansion disc made of a deformable material, and the shaped portion including a floor having an upper surface that supports and guides at least a portion of a bottom surface of the expansion disc. The outer peripheral surface of the bottom plate has the same shape as the outer peripheral edge of the expansion disk. The expansion disc is generally cup-shaped and in its normal non-expanded state the base plate has at least the same dimensions as the peripheral edge of the expansion disc. The shaped portion and the expansion portion are arranged such that axial movement of these parts towards each other causes the expansion disc to collapse from its cup shape such that its peripheral edge extends beyond the periphery of the base plate. The lid welding piston may be used as part of an apparatus for producing packaging containers and for introducing and positioning an inner flexible lid in a container tube and for pressing an edge portion of the flexible lid against an inner wall of the container tube during a welding operation for attaching the inner flexible lid to a container wall. The cap welding piston is introduced into the containment tube with the expansion disc in a non-expanded or normal state. When the flexible cover has been placed at the desired position within the container tube, the piston portion moves, thereby transforming the expansion disc into an expanded state, while the peripheral edge of the expansion disc extends beyond the periphery of the bottom plate, thereby causing the expansion disc to press the edge portion of the flexible cover against the inner wall of the container tube.

US patent publication US 4,989,394 a discloses a device similar to the device in EP 247986B 1. Thus, US 4,989,394 a discloses a radially expandable pressure plunger comprising two main parts, i.e. a shaped part and an expansion part which are movable relative to each other. The expansion portion is arranged to provide expansion of at least some portion of the pressure plunger when the main portions are moved together. The dilating portion comprises a cup-shaped dilating body and the forming portion is designed to have a forming surface against which at least a portion of the dilating body is adapted to slide when the forming portion and the dilating portion are axially moved towards each other. The expansion part consists of two different parts; an outer press-in part for carrying out an actual radially outwardly directed contact pressure of the pressure plunger and consisting of a wear-resistant, high-temperature-resistant and elastic material; and an inner bearing portion formed of a relatively hard, resilient material, the bearing portion bearing the pressed-in portion.

Document WO 2013/009226 a1 discloses an apparatus and a method for sealing containers based on cardboard. The apparatus comprises: a welding unit configured to secure the lid to the container, the welding unit comprising an induction welding energy generator for melting a weldable layer forming part of the container and/or lid; and a transport device configured to transport the flow of containers to and from the welding unit. The transport device comprises, in container flow order, a feeding means, a main conveyor member and a movable gripping means, wherein the feeding means is configured to transport containers one after the other to the main conveyor member in a continuous manner, wherein the movable gripping means is configured to transport containers from the main conveyor member to the welding unit, and wherein the apparatus is arranged such that, during normal operation of the apparatus, the containers are lined up against each other on an upstream side of the feeding means, wherein the feeding means is configured to, during operation, separate adjacent containers from each other in the transport direction by increasing a feeding speed of each individual container along the feeding means and thereby increasing a distance between adjacent containers fed along the feeding means, wherein the main conveyor member is configured to operate at a transport speed which substantially corresponds to and is consistent with a release speed of a container upon being fed from the feeder, such that containers transferred to and along the main conveyor member remain separated, wherein the movable gripping means are configured to grip at least two containers and transfer these containers simultaneously from the main conveyor member to the welding unit, and wherein the welding unit is configured to simultaneously secure a lid to each simultaneously transferred container. Document WO 2013/009226 a1 also discloses a method for operating an apparatus of this type.

Disclosure of Invention

It is an object of the present disclosure to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

The above object is achieved by the subject matter of claim 1. Embodiments are set forth in the appended dependent claims, in the following description and in the drawings.

Accordingly, the present invention relates to a positioning unit for positioning a container element in a container body, the positioning unit comprising:

a substrate comprising or consisting of a rigid material, an

-an elastically deformable plunger skirt.

The substrate has a footprint surface with a circumferential edge that includes a plurality of side edge portions connected by corner portions. The plunger skirt covers a surface of the base plate opposite the footprint surface.

At least one of the side edge portions of the peripheral edge of the substrate includes a curved section that curves in an inward direction from the peripheral edge of the footprint surface. The plunger skirt is transitionable between a non-expanded state and an expanded state. The plunger skirt has an outer circumference that is located at a circumferential edge of the footprint surface of the base plate in the unexpanded state and is located at least partially outside the circumferential edge of the footprint surface of the base plate in the expanded state.

The outer circumference of the plunger skirt in the non-expanded state preferably has a shape corresponding to the shape of the circumferential edge of the footprint surface, wherein at least one side of the outer circumference of the plunger skirt comprises a curved section which curves in an inward direction from the outer circumference of the plunger skirt.

The positioning unit comprises a first piston and a second piston extending in an axial direction, wherein the second piston is coaxial with the first piston. The base plate is connected to an end portion of the first piston such that a footprint surface of the base plate is perpendicular to the axial direction. A plunger skirt is connected to the end portion of the second piston. The first and second pistons are configured to be axially displaceable in synchronism with each other and independently of each other. The distal end portion of the second piston is configured to be closer to the distal end portion of the first piston than to the non-expanded state when the plunger skirt is in the expanded state.

As used herein, the term "container element" includes an element intended to be attached to a container body so as to form part of a container. Examples of container elements where transport plates may suitably be used are one or more of a bottom tray, a bottom rim, a lid, an upper rim and a sealing disc.

The base plate and the sealing disc are sheet-like parts which are applied inside the container body such that they cover the cross-section of the container body. The base pan forms a bottom end closure of the container and the sealing disc forms an internal shipping seal of the container. The sealing disc is usually placed at the container access opening, sometimes at a distance from the opening edge. The chassis and sealing disk may be made of paper, paperboard, plastic film, aluminum foil, and laminates of such materials. Typically, the chassis is made of a laminate of paperboard sheets coated with an outer layer of thermoplastic polymer material, and the sealing disc is a flexible member made of a laminate of one or more layers of aluminum foil and an outer layer of thermoplastic polymer material. However, sealing discs made of cardboard web material are also known in the art. The sealing disc is arranged to be partially or completely removed at the initial opening of the container and may be provided with opening means known in the art, such as a tear strip, a gripping tab or the like.

The upper and lower backing rings are typically made of a plastic material, such as a thermoformable plastic material, and take the form of a closed loop, the backing ring being applied to the container wall with at least a portion of the backing ring attached to the inner surface of the container wall. The rim may also cover the terminal edge of the container wall and extend onto the outer surface of the container wall.

The container may be a packaging container intended for containing bulk solids, in particular a cardboard packaging container.

As used herein, a "paperboard packaging container" is a packaging container in which the container body is formed from a paperboard web material. The paperboard container may be formed in any manner known in the art, such as by bending a paperboard web material into a tubular shape to form a container body and longitudinally closing the tube by connecting overlapping or abutting side edges of the sheets. The connection between the side edges may be covered by a sealing strip.

As used herein, a "paperboard web material" is a material made primarily of cellulose or paper fibers. The web material may be provided in the form of a continuous web or may be provided as separate pieces of material. The paperboard material may be a single or multiple layer material, and may be a laminate comprising one or more layers of material, such as polymeric films and coatings, metal foils, and the like. The polymer films and coatings may comprise or consist of thermoplastic polymers. The paperboard material may be coated, printed, embossed, etc., and may include fillers, pigments, binders, and other additives known in the art. Paperboard materials as disclosed herein may also be referred to as cardboard or carton materials.

As used herein, the term "bulk solids" refers to solid bulk materials in which a desired amount of product from among the bulk solids can be poured, scooped, or manually removed from a packaging container. The bulk material may be dry or moist. Bulk solids suitable for packaging in a paperboard packaging container as disclosed herein include any material in the form of particulates, granules, grinds, plant pieces, staple fibers, flakes, seeds, chips, and the like.

A paperboard packaging container as disclosed herein may be a container for food products such as infant formula, coffee, tea, rice, flour, sugar, cereals, soups, batters, pasta, snacks, etc. Alternatively, the bulk solids may be non-food, such as tobacco, detergents, fertilizers, chemicals, and the like.

The container elements may be made of cardboard, metal, plastic or any suitable combination of such materials as are known in the art. By way of example only: for example, if the container member is a chassis, the container member may be made of the same material as the container body. Alternatively, the container element may be made of plastic, for example if the container element is a bottom rim, an upper rim or a lid. The container member may also be made of metal, for example if the container member is a sealing disc.

Suitable materials for the substrate of the positioning unit are metals, alloys or ceramic composites. Suitable materials for the plunger skirt of the positioning unit are rubber or plastic. The plunger skirt is reversibly deformable, for example, to transition when a load is applied thereto. Furthermore, the plunger skirt is preferably able to return to its original shape when the load is removed.

The footprint surface of the substrate is configured to face the container element during production. The shape and size of the footprint surface is adapted to the shape and size of the container opening. The footprint surface is arranged to face the container opening during a process for producing the packaging container and is utilized when moving the container element into the container body and positioning the container element at a desired position inside the container body. The circumferential edge of the footprint surface may have a substantially polygonal shape, such as a substantially rectangular shape, wherein a square shape is herein considered as a special case of a rectangular shape. A generally polygonal shape as used herein refers to a shape having side edge portions connected by rounded corner portions. A base plate intended for use in applying a container element into a container body of generally polygonal cross-sectional shape with rounded portions is provided with a footprint surface having a circumferential edge with rounded portions to match the rounded portions of the container body. As stated herein, the substantially polygonal shape of the peripheral edge of the footprint surface of the substrate deviates from the ideal polygonal shape by a rounded corner and at least one curved section that curves inwardly.

A plunger skirt is disposed on top of the base plate, covering an upper surface of the base plate opposite the footprint surface. Thus, when the plunger skirt is in the non-expanded state, the plunger skirt will not contact the container element or will at least not exert any force on the container element during insertion of the container element into the container body interior at the pre-selectable desired attachment position. When the container element has reached the attachment position, the plunger skirt may be expanded in a radial direction, thereby pressing the rim portion of the container element circumferentially against the inner side of the container wall of the container body. In this expanded state of the plunger skirt, the cross-section defined by the outer circumference of the plunger skirt is larger than the cross-section in the non-expanded state of the plunger skirt.

By providing at least one curved section of the circumferential edge of the footprint surface of the base plate and a corresponding at least one curved section of the outer circumference of the plunger skirt, the risk of the positioning unit touching the upper edge of the container body and thereby damaging the tubular wall of the container body upon insertion of the container element may be substantially reduced or avoided.

In the non-expanded state of the plunger skirt, the outer contour of the plunger skirt preferably corresponds to the contour of the base plate. Thus, the outer circumference of the plunger skirt preferably has the same or substantially the same shape as the circumferential edge of the footprint surface of the base plate. The outer circumference of the plunger skirt is located at a circumferential edge of the baseplate, such as within 3mm from the circumferential edge of the footprint surface of the baseplate, within 2mm from the circumferential edge of the footprint surface of the baseplate, or within 1mm from the circumferential edge of the footprint surface of the baseplate, when viewed relative to the baseplate. Preferably, the outer circumference of the plunger skirt coincides with or is slightly inside of the circumferential edge of the footprint surface of the base plate when the plunger skirt is in the non-expanded state.

During transition to the expanded state, the plunger skirt will be flattened and the inwardly curved section will simultaneously straighten out, at least to the extent that the outer circumference of the plunger skirt extends beyond the circumferential edge of the footprint surface. Thus, by carefully selecting the shape and/or material properties of the plunger skirt in the non-expanded state, the desired shape change during the transition may be obtained. The material for the plunger skirt may be any useful elastically deformable, wear and heat resistant material known in the art, such as natural or synthetic rubber materials, e.g., polyamide, polyurethane, polyester, and the like.

While not wishing to be bound by theory, it is believed that with the proposed shape of the plunger skirt, when transitioning the plunger skirt to the expanded state, the curved sections of the outer circumference of the plunger skirt will move outwardly, causing the distance between adjacent corner portions to increase as the plunger skirt flattens, thereby stretching the outer circumference of the plunger skirt and pulling out the curved section or sections. Thus, the shape of the outer circumference of the plunger skirt is altered such that inward bending of the one or more bending sections is reduced or eliminated. Since the plunger skirt is made of or comprises an elastically deformable material, the shape change that occurs during the transition is reversible, which means that the plunger skirt will automatically return to the non-expanded state once the deforming force that caused the transition to the expanded state is removed.

Preferably, at least two of the plurality of side edge portions of the circumferential edge of the substrate, or more preferably each side edge portion of the circumferential edge of the substrate, comprise a respective curved section.

It is sufficient to arrange the curved section only at one side of the peripheral edge of the footprint surface of the base plate and the outer circumference of the plunger skirt. When only a single curved section is employed, it is preferably positioned at a location corresponding to the connection in the container body. As described above, the connection may be created by bending a paperboard web material into a tubular shape to form the container body and longitudinally closing the tube by connecting overlapping or abutting side edges of the sheets. The connection between the side edges may be covered by a sealing strip. This connection locally thickens the wall of the container plate and also risks bending or bulging inwards towards the interior of the container body. Due to the curved section of the side edge portion of the substrate, the substrate may pass such a potentially inwardly protruding connection without causing damage thereto when the positioning unit introduces the container element into the container body and moves the container element to an attachment position in the container body.

However, assuming that the shape of the positioning unit is mirror-symmetrical, by arranging the two side edge portions with respective curved sections, the positioning unit can be rotated 180 degrees to, for example, even the wear. If the positioning unit has a substantially square shape, it may be advantageous to arrange four equal side edge portions with corresponding curved sections such that the positioning unit can be rotated in steps of 90 degrees. Furthermore, by providing curved sections at more than one side edge portion of the positioning unit, the risk of damaging other portions of the container wall than possible connections is greatly reduced or avoided. When producing a container having a polygonal or substantially polygonal cross-sectional shape, it may be preferred that the inwardly curved sections are arranged at all corresponding sides of the positioning unit to avoid or minimize the risk of the positioning unit coming into contact with and potentially damaging any part of the container body edges and container body walls.

The transition of the shape change of the plunger skirt may be obtained by the bending section of the side of the outer circumference of the plunger skirt bending less in the expanded state of the plunger skirt than in the non-expanded state. Thus, the bending of the curved portion is reduced, eliminated or reversed in the expanded state compared to the non-expanded state. Preferably, the bending section is fully straightened, or the bending section is given a slightly outwardly convex curvature, so that the inward bending is eliminated in the expanded state.

Thus, the curvature of the curved section of the side of the outer circumference of the plunger skirt may be varied by elastically transforming the plunger skirt from the non-expanded state to the expanded state such that the curved section is less curved in an inward direction in the expanded state of the plunger skirt, or the curved section is straight in the expanded state of the plunger skirt, or the curved section is curved in an outward direction away from the outer circumference of the plunger skirt in the expanded state of the plunger skirt.

The inwardly curved section of the side edge portion of the peripheral edge of the footprint surface of the substrate may extend from the rounded corner portion all the way to an adjacent rounded corner portion of the substantially polygonal shape. This means that the entire side edge portion is curved such that there are no straight sections on the side edge portion. Correspondingly, the curved section of the side of the circumferential edge of the plunger skirt in the non-expanded state may extend from the rounded portion to an adjacent rounded portion of the substantially polygonal shape.

In the plunger skirt having a polygonal outer circumference, a minimum distance d from the outer circumference of the plunger skirt to a center of the polygonal shape of the plunger skirt in an expanded state_eMay be greater than a minimum distance d from an outer circumference of the plunger skirt to a center of the polygonal shape of the plunger skirt in a non-expanded state_oPreferably at least 1mm, such as at least 2mm, at least 4mm or at least 8 mm.

The base plate has an extension (thickness) in a height direction z perpendicular to the footprint surface, wherein the extension in the height direction z may be larger at the rounded corners than at adjacent curved sections of the at least one side edge portion. This is beneficial in order to create an increased pressure in the radial direction at the corner portions of the container body. When pressure is applied to the plunger skirt to change the shape of the plunger skirt from the non-expanded state to the expanded state, the corner portions of the plunger skirt typically move outwardly a shorter distance than the sides between the corner portions. By way of example, when the side portions are moved outwardly by about 4mm, the corner portions may only be moved outwardly by half that distance, i.e. about 2 mm. A thickened corner portion is provided on the upper surface of the base plate, i.e. on the surface of the base plate opposite the footprint surface of the base plate, for forcing the plunger skirt further out, thereby exerting an increased pressure on the applied container element and improving the contact between the container element and the corner portion of the container body. The enhanced contact pressure may be particularly beneficial at corner portions of the container body, where wrinkles arising from folding the peripheral edge portion of the disc-shaped container element into alignment with the container wall may lead to problems with forming a tight seal between the container element and the container wall.

When inserting the container element into the attachment position in the container body, the first piston and the second piston of the positioning unit are axially displaced in synchronism with each other, i.e. they move together as a single unit. When transforming the plunger skirt into the expanded state, they are displaced independently of each other such that the second piston is displaced in axial direction relative to the first piston. Thereby, the plunger skirt is pressed down on the base plate and flattened out, so that the outer circumference of the plunger skirt is caused to assume an expanded state, thereby changing the shape of the plunger skirt under the influence of the relative movement of the two pistons. The resiliently deformable plunger skirt will automatically return to the non-expanded state once the pressure exerted on the plunger skirt from the first and second pistons ceases after application of the container element at the desired location inside the container body.

The invention also relates to an attachment unit for attaching a container element to a container body. The attachment unit comprises holding means adapted to hold the container body when attaching the container element to the container body. The attachment unit further comprises a positioning unit as described herein. The retaining means comprises at least one locating cavity therethrough adapted to receive a portion of the container body. The positioning unit is aligned with the positioning cavity such that the container element can be displaced into the container body by means of the positioning unit by moving the container element at least partially through the positioning cavity of the holding device.

The attachment unit may comprise a support means adapted to support the container body and position the container body in the holding means. The support means may for example insert the container body into the holding means from below and move the container body upwards until it reaches the desired pre-selected position.

The orientation of the container body depends on the container element to be attached. By way of example only: if a lid or upper rim is attached, the container body is preferably held with the upper opening facing upwards. However, if a bottom tray or bottom rim is attached, the container body is preferably held with the bottom opening facing upwards. The sealing disk may be attached from either of the two container openings.

The positioning unit is adapted to position the container element in the container body and in vertical alignment with a positioning cavity in the holding device. The positioning unit may be vertically adjustable and may be capable of pressing the container element down into the container body to a desired preselected attachment position. Further, as described above, the plunger skirt of the positioning unit may be expanded in the radial direction of the positioning chamber. Thereby, it is possible to have the edge portion of the outer circumference of the plunger skirt circumferentially exert a pressure on a vertical portion of the container element (such as a folded edge portion of the chassis) in a direction towards the wall of the positioning chamber. In this way, the outer circumference of the plunger skirt will be pressed against the inside of the container wall of the container body placed in the positioning chamber. The edge portion of the outer circumference of the plunger skirt, which is arranged to be in contact with and to exert pressure on the container element in the expanded state of the plunger skirt, may have a contact surface which is slightly inclined with respect to the vertical direction of the positioning unit in the non-expanded state of the plunger skirt.

The retaining means may comprise a liner located in the positioning cavity and arranged to shield an exposed edge of the container body. The lining is preferably applied such that it surrounds the positioning cavity, thereby locally reducing the cross-section of the positioning cavity. The thickness of the liner may be the same as the thickness of the sheet material used for the container body, and may be in the range of 0.2mm to 2mm, such as 0.5mm to 1.5mm or 0.6mm to 0.9 mm. This will for example help when folding the edge portions of the sealing disc or the chassis.

The holding device may comprise a welding unit preferably arranged around the positioning cavity. The welding unit is adapted for welding the container element to the container body, for example the welding unit comprises a coil extending around the positioning cavity. Any suitable welding technique may be used, such as ultrasonic welding or high frequency welding, with high frequency welding being preferred. If, as mentioned above, the positioning unit can be expanded in the radial direction of the positioning chamber, the container element can be pressed against the welding unit

As an alternative or in addition to welding, an adhesive may be applied to the container element prior to attaching the container element to the container body. However, this requires additional components to be added to the container and additional equipment for supplying and applying the adhesive.

The attachment unit may further comprise a transport plate for transporting the container element between the first position and the second position. The transfer plate comprises at least one through-going transfer cavity adapted to receive and hold a container element. The transport plate is displaceable between a first position in which the transport plate is adapted to accommodate container elements in the transport chamber and a second position in which the transport chamber is aligned with the positioning chamber of the holding device, the transport plate being located between the positioning unit and the positioning chamber of the holding device in the second position, such that container elements are displaceable from the transport chamber in the transport plate into the container body by means of the positioning unit by moving the container elements through the transport chamber and at least partly through the positioning chamber of the holding device. Additional positions, such as intermediate positions therebetween, may also be present.

The through-going transfer cavity of the transfer plate may have a smaller cross-section than the positioning cavity of the holding device. The difference may correspond to the thickness of the container wall, which is typically in the range of 0.2mm to 2mm, such as 0.5mm to 1.5mm or 0.6mm to 0.9 mm. This would for example be helpful when folding over the edge portions of the inserted container element and could be used as an alternative or supplement to the liner described above.

The transfer plate may comprise one or more holding elements adapted to hold the container elements in the transfer chamber. The one or more holding elements may be located at a wall of the transfer chamber, preferably in the centre of one side of the wall. One, two, three, four or more retaining elements may be provided. There may be, for example, four such retaining elements adapted to retain each side of the container element in the case of a container having a substantially rectangular or square shape. The retaining element is then preferably located at the centre of each side of the substantially rectangular or square transfer chamber wall. The retaining element may be elastic, for example due to material properties or being spring biased. Alternatively or additionally, the container element itself may be elastic, for example due to material properties. The holding element may be used to compensate for tolerances with respect to the dimensions of the container element and/or the transfer chamber. In addition or as a supplement, the retaining element may be used to temporarily press the sides of the container element (e.g. the bottom rim) inwards, so that the container element will be easier to insert into the container body, thereby reducing or avoiding the risk of damaging the edges of the container body during insertion of the container element.

If the above-described retaining elements are used in the transfer plate, the expandable plunger skirt may help to return the inwardly pressed container element to its original shape in case the container element lacks sufficient elasticity to recover the original shape in the absence of an external influence.

To facilitate the placement of the container element in the transfer chamber, one or more recesses may be arranged around the transfer chamber to leave room for one or more gripping members for placing the container element in the transfer chamber. The notch does not form a hole through the transmission plate.

If a retaining element is provided in the transmission plate as described herein, the notch is preferably positioned so as not to interfere with the retaining element. Thus, the notch may be located in a corner of the transmission cavity. Such clamping members and corresponding recesses arranged at the periphery of the transfer chamber are particularly useful for annular container elements, such as top or bottom backing rings, comprising an inner volume filled with a gas, e.g. air.

If the container element is a sheet-like container element, such as a bottom tray, a lid or a sealing disc, the container element may alternatively be placed into the transfer chamber by means of, for example, a suction cup.

The holding device may comprise a plurality of positioning cavities, and the attachment unit may comprise a plurality of positioning units aligned with the positioning cavities as described herein, such that each positioning unit is associated with a respective positioning cavity, the positioning cavities and the positioning units preferably being arranged in rows. The plurality may be two, three, four, six, eight, ten or more positioning chambers and/or positioning units.

Further, the optional transmission plate may comprise a plurality of cavity portions, each cavity portion comprising a respective transmission cavity and being arranged with a corresponding cover portion. The holding device may then comprise a corresponding plurality of positioning cavities. The optional support means may be adapted to support a respective plurality of container bodies and position the container bodies in the positioning cavity of the holding means.

The plurality of positioning units may be adapted to simultaneously position a plurality of container elements in the respective container bodies. It has been found suitable to attach a plurality of container elements to respective container bodies simultaneously in order to increase the operating speed of the device. By way of example only, two, three, four, six, eight, ten or more container elements may be attached simultaneously.

The invention also relates to an apparatus for attaching a container element to a container body in a flow of the container. The apparatus comprises a transport device configured to transport a stream of containers through the apparatus, and at least one attachment unit as described herein, the at least one attachment unit being arranged along the transport device.

The conveying means may comprise one or more conveyor members at respective opposite sides of the container body, feeding means, for example in the form of two feed screw members, and/or one or more movable gripping means. The components of the transport device may be similar to those described in the above-mentioned published patent application WO 2013/009226 a1, to which reference is made for additional details. The transport device is arranged to transport the container body to and from the attachment unit.

The apparatus may comprise a plurality of attachment units as described herein arranged at different positions along the transport device and configured for attaching different container elements to the container body. A first attachment unit may be arranged to attach a disc-shaped element, e.g. a bottom disc or an inner sealing disc, to the container body, and a second attachment unit, as described herein, may be arranged to attach a reinforcing rim, e.g. a bottom or top rim, to the container body, the second attachment unit being located downstream of the first attachment unit. The transport means is adapted to transport the container body to the first attachment unit, between the attachment units and/or onwards from the second attachment unit.

The device may comprise a further attachment unit as described herein. There may be an attachment unit, for example, for one or more of the container elements described herein (i.e., the chassis, bottom rim, cover, upper rim, or sealing disk). Furthermore, a single attachment unit may be used to attach more than one container element.

The apparatus may comprise an outer housing arranged to enclose the transportation device and the at least one attachment unit. The outer housing may serve to protect the device from external interference. The outer housing may be adapted to provide and maintain a protective atmosphere. The protective gas may be nitrogen, carbon dioxide, and mixtures of nitrogen and carbon dioxide. Preferably, the outer casing forms an air chamber which is as closed as possible in order to minimize the loss of protective gas and/or to minimize the ingress of ambient air.

The attachment unit may optionally comprise an inner housing located within the outer housing and arranged to be above the positioning cavity of the holding device to provide an additional protective atmosphere. The outer casing and the inner casing may together act as a two-stage shield around the transportation device and the at least one attachment unit to ensure that the attachment of the container element may be performed in a protective atmosphere with minimal loss of protective gas.

The invention also relates to a method of positioning a container element in a container body by means of a positioning unit as described herein. The method comprises the following steps:

-moving the container element to a pre-selectable position in the container body by means of a positioning unit inserting the container element into the container body, the plunger skirt thereby being in a non-expanded state,

-transforming the plunger skirt into an expanded state when the container element reaches the pre-selectable position, thereby pressing the rim portion of the container element in a direction towards the inner wall of the container body.

As mentioned above, the step of transforming the plunger skirt into the expanded state may be performed by means of a relative displacement between the first piston and the second piston, wherein the tip portion of the second piston moves closer to the tip portion of the first piston. When the outer ends of the first and second pistons are brought together, the end portion of the second piston, which is attached to the plunger skirt, moves towards the base plate and applies pressure to the plunger skirt between the end portion of the second piston and the base plate. Pressure on the elastically deformable plunger skirt flattens the plunger skirt so that the size of the plunger skirt decreases in the axial direction of the positioning unit while the outer circumference of the plunger skirt expands outward in the radial direction of the positioning unit by sliding on the surface of the base plate opposite to the footprint surface. Thus, the shape of the plunger skirt changes under the influence of a compression force acting in the axial direction between the end portion of the second piston and the base plate at the end portion of the first piston.

The method may further comprise:

-fixing the container element to the container body, for example by means of welding and/or adhesive.

If the attachment unit comprises a transmission plate as described herein, the method may comprise:

-placing the container element in a transfer chamber,

-displacing the transport plate to the second position,

-displacing the container elements from the transport chamber in the transport plate into the container body by means of the positioning unit by moving through the transport chamber and at least partly through the positioning chamber of the holding device.

If the attachment unit comprises a plurality of positioning units, the method may comprise: simultaneously positioning a plurality of container elements into the respective container bodies by the positioning unit.

Drawings

The invention will be further explained below, by way of non-limiting example, with reference to the accompanying drawings, in which:

fig. 1 shows in perspective view an apparatus according to the invention for attaching a container element to a container body in a flow of containers.

Fig. 2 shows the interior of the device of fig. 1.

Fig. 3 shows an exemplary container to which the apparatus is adapted.

Fig. 4 shows an attachment unit for attaching a container element according to the invention, wherein the transport plate is in a first position.

Fig. 5 shows the attachment unit of fig. 4 with the transmission plate in a second position.

Fig. 6 shows a transmission plate.

Fig. 7 shows a positioning unit, a sealing disc and a container body according to the invention.

Fig. 8 shows a footprint surface (footprint surface) of a substrate included in the positioning unit.

Fig. 9 shows the footprint surface of a substrate according to the prior art.

Fig. 10 shows the outer circumference of the plunger skirt comprised in the positioning unit in a non-expanded state.

Fig. 11 shows the outer circumference of the plunger skirt of fig. 10 in an expanded state.

Fig. 12a shows the positioning unit with the plunger skirt in a non-expanded state.

FIG. 12b shows the positioning unit with the plunger skirt in an expanded state

Fig. 13a shows a cross-section through the positioning unit with the plunger skirt in a non-expanded state.

Fig. 13b shows a section through the positioning unit with the plunger skirt in an expanded state.

It should be noted that the figures are schematic and that the various components are not necessarily drawn to scale, and that the dimensions of some of the features of the invention may have been exaggerated for clarity.

Detailed Description

Hereinafter, the present invention will be illustrated by embodiments. It should be understood, however, that these embodiments are included to explain the principles of the invention and not to limit the scope of the invention as defined by the appended claims. Details from two or more embodiments may be combined with each other.

Fig. 1 and 2 show a device 1 according to the invention for attaching a container element to a container body in a flow of containers. Fig. 3 shows an exemplary container 101 to which the device 1 is adapted.

The apparatus 1 comprises a transport device 3 configured to transport a stream of containers through the apparatus 1 and an attachment unit 5 for attaching container elements to container bodies. The outer housing 7 is arranged to enclose the carrier 3 and the attachment unit 5. Fig. 1 shows a perspective view of a device 1.

Fig. 2 shows the interior of the device 1 with the outer housing 7 removed for better visibility.

As shown in fig. 3, the apparatus 1 is suitable for producing a cardboard packaging container 101 for pourable or spoonable bulk solids. The particular shape of the container 101 shown in the figures should not be considered limiting to the invention, as the apparatus 1 is suitable for use with any useful shape or size of container. It should also be understood that the container elements shown in connection with container 101 in fig. 3 are not limiting to the invention. Thus, the positioning unit, the attachment unit, the apparatus and the method of positioning container elements disclosed herein may be used to produce containers having fewer or more container elements than the container 101 shown in fig. 3. Furthermore, the container elements may have different size, shape and functional characteristics than those shown in fig. 3. By way of example, the upper edge may be provided with a scoop clip and/or a scraper. The closure mechanism on the lid may differ from the mechanism disclosed in connection with fig. 3 etc.

The vessel 101 comprises a vessel body 103 formed by a tubular vessel wall 105. The container wall 105 extends in the height direction H of the container 101 from a bottom end edge 107 at the bottom end of the container body 103 to an upper end edge 109 at the upper end of the container body 103. The container body 103 has an upper opening 111 at an upper end and a bottom opening 113 at a bottom end. A bottom tray 115 is located at the bottom end of the container body 103 and covers the bottom opening 113. The container body 103 is made of a paperboard material as defined herein. The container body 103 may be formed by bringing the side edges of a cardboard web (paperboard web) together so that the material assumes a tubular shape, and subsequently sealing the side edges together. The sealing of the side edges may be performed by any suitable method as known in the art, such as by welding or gluing, wherein welding (such as induction welding) is preferred. As is known in the art, sealing of the side edges of the container body web may involve the use of a sealing strip which is applied over the connection between the side edges. The chassis 115 may be made of cardboard, metal, plastic, or any suitable combination of such materials as are known in the art. The bottom disk 115 may have a folded edge portion 116 forming a wall for attaching the bottom disk 115 to the inner surface of the vessel wall 105.

The bottom end edge 107 is reinforced by a reinforcing bottom rim (bottom rim)117 applied to the inner surface of the vessel wall 105 between the bottom disc 115 and the bottom end edge 107 and/or to a folded edge portion 116 of the bottom disc 115. In the illustrated embodiment, the bottom rim 117 has an outwardly directed flange 119 that covers the bottom end edge 107 and forms the bottom edge of the container 101. The bottom rim 117 reinforces the bottom edge 107, stabilizes the shape of the container body 103, and protects the bottom edge 107 from mechanical deformation. The bottom rim 117 also serves as a protective barrier against water and other fluids that may be present on the surface on which the container 101 is placed. The bottom rim 117 defines a downwardly open space between the bottom disc 115 and the bottom edge of the container 101, which space may be used for accommodating stacking elements arranged at the upper end of another container when two or more containers are stacked on top of each other. A reinforced bottom rim is an optional feature of the packaging container disclosed herein.

As an alternative to the bottom rim 117 shown, the bottom edge of the container may be formed by a bead of the container body 103 or may be provided by a simple, non-rolled connection between the chassis 115 and the container body 103.

The container 101 is provided with a closure means comprising a lid 121 and a reinforced upper rim 123 extending along the container opening edge 109. The cover 121 includes a planar disk 125. The exemplary container 101 is also provided with a fully or partially removable sealing disk 127 that is adapted to seal to the container body wall 105.

The bottom disk 115, bottom rim 117, cover 121, upper rim 123 and sealing disk 127 are examples of container elements for which the apparatus 1 is adapted for attaching the container elements to the container body 103.

The bottom and upper backing rings 117, 123 are typically made of a plastic material, preferably a thermoplastic material. As can be taken from fig. 3, the bottom rim 117 and the upper rim 123 form a closed loop, the main extension of which is in the loop plane. The closed loop centrally encloses an open space. The bottom rim 117 and the upper rim 123 also have a corresponding extension in the height direction H of the container 101, thereby forming

corresponding edge portions

129, 131 of the container elements. Thus, the closed loops define the interior volumes of the bottom and upper backing rings 117 and 123, respectively.

The bottom disc 115, lid 121 and sealing disc 127 are adapted to extend across the cross-section of the container body 103 and form a cross-sectional seal or closure. The edge portion 133 of the sealing disk 127 is folded up or down so that it conforms to the interior of the container wall 105 and attaches to the interior of the container wall 105. Likewise, the bottom tray 115 and the lid 121 each have a folded

edge portion

116, 135 extending in the height direction H of the container 101. The interior volume of the container 101 is defined between the floor 115 and the lid 121. The gland plate 127 forms a shipping seal at the upper end of the container 101 and defines an internal shipping volume between the gland plate 127 and the bottom disk 115. The sealing disc 127 is adapted to be completely or partially removed by a user of the container 101 in order to gain a first access to the package contents in the container 101.

Returning again to fig. 1 and 2, it can be seen that the conveyor feeds the container bodies 103 to the apparatus 1. Another conveyor feeds the containers 101 away from the apparatus 1. In the exemplary illustrated embodiment of the device 1, it is assumed that the material to be contained in the container 101 has been filled into the interior of the container body 103 in a filling unit located upstream of the device 1.

Fig. 2 shows the interior of the device 1. Along the running direction R of the apparatus 1, the conveying means 3 comprise an inlet conveyor member 9, feeding means 11 in the form of two feed screw members arranged at respective opposite sides of the container body 103 (one of which can be seen in fig. 2), a main conveyor member 13, a first movable clamping means 15, a second movable clamping means 17, an outlet conveyor member 19 arranged downstream of the attachment unit 5, and a fixed slide plate 21 arranged at the outlet of the apparatus 1. The

components

9, 11, 13, 15, 17, 19, 21 of the conveying device 3 constitute examples and are similar to those described in WO 2013/009226 a1, to which reference is made for further details.

The attachment unit 5 is located between the main conveyor member 13 and the exit conveyor member 19, as seen in the running direction R of the apparatus 1. The attachment unit 5 is further described below in connection with fig. 4 and 5. The first movable gripping means 15 and the second movable gripping means 17 move the container main body 103 to and from the attachment unit 5. In the embodiment shown in fig. 1 and 2, the attachment unit 5 is adapted to attach a shipping seal in the form of a sealing disc 127 inside the container body 103. It has been found suitable to attach a plurality of sealing discs 127 to a plurality of corresponding container bodies 103 simultaneously in order to increase the operating speed of the apparatus 1. In the illustrated embodiment, four sealing discs 127 are attached to respective container bodies 103 simultaneously. Alternatively, the sealing discs 127 may be attached to the container simultaneously in any other number of groups than four (e.g., two, three, six, eight, or ten), or may be attached to the container sequentially.

As described herein, the device 1 may comprise one or more additional attachment units adapted to attach other container elements to the container body 103. Any such additional attachment unit will be located upstream or downstream of the illustrated attachment unit 5. Similar to the attachment unit 5 shown, the additional attachment unit is preferably arranged to attach the container element to a plurality of container bodies 103 simultaneously, preferably for the same number of container bodies 103 as the attachment unit 5 used for the display.

The outer housing 7 encloses the carrier device 3 and the at least one attachment unit 5. The outer casing 7 is adapted to protect the device 1 and/or to provide and maintain a protective atmosphere inside the device 1. The protective gas may be nitrogen, carbon dioxide, and mixtures of nitrogen and carbon dioxide. It is therefore preferred that the outer casing 7 forms an air chamber which is as closed as possible in order to minimize the loss of protective gas and/or to minimize the ingress of ambient air into the chamber formed by the outer casing 7. However, the outer case 7 may be opened downward.

As an option, the container may be degassed as material, such as bulk solids, is filled into the container. Degassing may include supplying a protective gas to the flow of material to be contained in the container during filling. The protective gas may be nitrogen, carbon dioxide, and mixtures of nitrogen and carbon dioxide. A protective gas may be blown into the stream of material before the material reaches the container. If the material is treated with a protective gas during filling, the container is preferably transported to the apparatus 1 while maintaining a protective atmosphere, for example by moving the container through a tunnel filled with the protective gas. Alternatively, the filled container may be introduced into a vacuum chamber to evacuate the air, followed by subjecting the container to a protective atmosphere and closing.

Even if it is assumed in the embodiment shown that the material to be contained in the container has already been filled in the container upstream of the device 1, the filling unit can be positioned inside the outer casing 7 of the device. In this case, the outer housing may enclose the filling unit and/or one or more units for attaching the sealing disc 127, the upper backing ring 123 and the cover 121.

Fig. 4 and 5 show an attachment unit 5 for attaching a container element according to the invention. The illustrated embodiment shows the attachment of the upper grommet 123. However, such an attachment unit 5 would also be suitable for attaching any other container element described herein, i.e. sealing disc 127, bottom disc 115, bottom rim 117 or cover 121. The attachment unit 5 includes a holding device 23, a supporting device 25, a positioning unit 27, and a transfer plate 29.

An example of the transmission plate 29 is shown in fig. 6. The transport plate 29 extends in a first direction x parallel to the running direction R of the apparatus 1 and in a second direction perpendicular to the first direction x and coinciding with the transverse direction of the apparatus 1. The transfer plate 29 comprises a cavity portion 31 having at least one through-going transfer cavity 33 adapted to receive and hold a container element, in this case an upper rim 123 or a bottom rim 117. The transfer chamber 33 has a first opening area A₁And is configured to hold the container element.

Alternatively, the transfer plate 29 may be omitted such that a container element, such as a sealing disk 127, is placed directly on top of the holding device 23.

In order to minimize or preferably avoid unnecessary loss of protective gas, the shape of the transfer chamber 33 is made to correspond to the shape of the container element, e.g. the upper rim 123 or the bottom rim 117. In case the container element comprises edge portions that are to be folded when the container element is inserted into the container, as in the case of the bottom plate 115 or the sealing plate 127, the first opening area Α of the transfer chamber 33₁May be smaller than the surface area of the container element before folding, wherein the difference in area corresponds to the area of the part of the container element forming the folded edge portion. Such folded edge portions are typically strip-shaped and may have a width in the range of 1mm to 10mm, preferably in the range of 2mm to 5 mm. Thus, the folded edge portions on the sheet-like container element, such as a sealing disc or a bottom disc, may be formed by: the container element is pressed down through a transfer chamber having a smaller cross-section than the container element, forcing the sheet-like container element to fold at the edge of the transfer chamber to be accommodated in the first opening area A of the transfer chamber₁And (4) the following steps.

The walls of the transfer chamber 33 may comprise a holding element 34 adapted to hold the container element in the transfer chamber 33. See fig. 6. Such a holding element 34 is particularly useful for container elements such as a rim (such as a bottom rim 117 or an upper rim 123) which do not have a disc shape but rather form a ring comprising an inner volume filled with a gas, for example air. For a disc-shaped container element, such as the bottom disc 115, the cover 121 or the sealing disc 127, the holding element 34 may be omitted.

In the embodiment shown, there are four such retaining elements 34 adapted to retain each side of the container element, which in the embodiment shown is substantially rectangular or square, preferably in the centre of each side. It would be feasible to use one, two, three, four or more such retaining elements 34. The retaining element 34 may be elastic, for example due to material properties or spring-biased. Alternatively or additionally, the container element itself, such as the rim, may be elastic, for example due to material properties. The holding element 34 may be used to compensate for tolerances with respect to the dimensions of the

container elements

115, 117, 121, 123, 127 and/or the transfer chamber 33. In addition or as a supplement, the retaining element 34 may be used to temporarily press the sides of the container element (e.g. the bottom rim 117) inwards, so that the container element will be more easily inserted into the container body 103, thereby reducing or avoiding the risk of damaging the edge of the container body 103 during insertion of the bottom rim 117.

As shown in fig. 4, 5 and 6, the transfer plate 29 may optionally include a cover portion 35 that is in contact with at least the first opening area a of the transfer chamber 33₁As large or substantially as large. The cover portion 35 is arranged adjacent to the cavity portion 31 as seen in the second direction y. The cover part 35 has a minimum extension y in the second direction y₁The smallest extension being in the area A of the transmission chamber 33₁Of the second direction y₂At least 1.0 times, preferably at least 1.2 times, more preferably at least 1.4 times. The use of a cover part 35 is advantageous when the container element is ring-shaped, i.e. when the container element is not in the form of a disc, which, after its application to the interior of the container body, will form a seal over the container openingAnd prevents gas from escaping through the container body.

To facilitate the placement of the

container elements

115, 117, 121, 123, 127 into the transfer cavities 33 of the transfer plate 29, notches 36 may be provided as shown in fig. 6. The recess 36 leaves room for gripping

members

44a, 44b, 44c, 44d, which are arranged to move the container elements into the transfer chamber 33. See fig. 4 and 5 and further description of the clamping member below. If a retaining element 34 is utilized, the notches 36 are preferably positioned so that they do not interfere with the retaining element 34. Thus, the notch 36 may be located in a corner of the transmission cavity 33. Such

gripping members

44a, 44b, 44c, 44d and their corresponding recesses 36 are particularly useful when the container element is formed as a ring comprising an inner volume filled with a gas, such as air, such as a bottom or top rim.

If the container element is disc-shaped, such as a bottom disc 115, a cover 121 or a sealing disc 127, the

container element

115, 121, 127 may alternatively be placed into the transfer chamber 33 by a holding means, such as one or more suction cups. In this case, the notch 36 may be omitted. However, when the container element forms a loop, the suction cup is not suitable.

In the embodiment shown, there are four cavity portions 31 arranged in a row as seen in the first direction x. Each cavity portion 31 comprises a respective transfer cavity 33 and is arranged with a corresponding respective cover portion 35.

The holding means 23 is adapted to hold the container body 103 when attaching the container element to the container body 103. The holding device 23 comprises at least one through positioning chamber 37 having a first open area a corresponding to the transfer chamber 33₁Second opening region a₂The positioning cavity 37 is adapted to receive a portion of the container body 103. If a cover part 35 is present, the size and shape of the cover part 35 of the transmission plate 29 is selected such that the cover part 35 is able to cover or at least substantially cover the second opening area A of the positioning chamber 37₂。

The support means 25 is adapted to support the container body 103 and to position the container body 103 in the holding means 23.

The positioning unit 27 is adapted to position the

container elements

115, 117, 121, 123, 127 in the container body 103. Thus, the positioning unit 27 is aligned with the positioning cavity 37 as seen in the vertical direction z. The positioning unit 27 is vertically adjustable and is capable of inserting the container element into the container body 103 to a desired pre-selectable attachment position. As described in more detail below, it is possible to expand the positioning unit 27 in the radial direction of the positioning chamber 37 and to press the vertical portion of the container element circumferentially in a direction towards the wall of the positioning chamber 37, see the

edge portions

116, 129, 131, 133, 135 of fig. 3, i.e. against the inside of the container wall 105 of the container body 103 placed in the positioning chamber 37.

In the illustrated embodiment of the attachment unit 5, the transmission plate 29 comprises four cavity portions 31 arranged in rows as seen in the first direction x. In a corresponding manner, the holding device 23 comprises the same number (i.e. four) of positioning cavities 37. Furthermore, the supporting means 25 are adapted to support an equal number (i.e. four) of container bodies 103 and position a portion of them in the corresponding positioning cavity 37 of the holding means 23. Furthermore, the attachment unit 5 comprises the same number (i.e. four) of positioning units 27 aligned with the positioning cavities 37, so that each positioning unit 27 is associated with a respective positioning cavity 37. With this configuration, a plurality of container elements, here four, can be attached simultaneously. Similar to the transmission plate 29, the positioning cavities 37 and the positioning units 25 are arranged in rows as seen in the first direction x.

The transmission plate 29 is displaceable between a first position and a second position. As shown in fig. 4, in the first position the transfer plate 29 is arranged to accommodate the container elements in the transfer chamber 33, while the cover portion 35 covers or substantially covers the second opening area a of the positioning chamber 37₂. Thereby, loss of protective gas through the positioning chamber 37 may be minimized or preferably avoided. As shown in fig. 5, in the second position, the transfer chamber 33 is aligned with the positioning chamber 37 of the holding device 23 and thus also with the positioning unit 27. The transfer plate 29 is initially positioned vertically between the positioning unit 27 and the positioning chamber 37 of the holding device 23. From this position, the positioning unit 27 is moved at least partially through the transport chamber 33 by moving downwards in the z-directionOver the positioning cavity 37 of the holding device 23, thereby displacing container elements from the transfer cavity 33 in the transfer plate 29 into the container body 103. In the embodiment shown in fig. 4 and 5, the container element is constituted by an upper rim 123.

For attaching the container element to the container body 103, the holding device 23 may comprise a welding unit 39, which is preferably arranged around the positioning cavity 37. The welding unit 39 is adapted for welding the container elements to the container body 103, for example by means of the welding unit 39 comprising a coil extending around the positioning chamber 37. As described herein, since the positioning unit 27 can be expanded in the radial direction of the positioning chamber 37, the container element can be pressed against the welding unit 39. Any suitable welding technique may be used, such as ultrasonic welding or high frequency welding, with high frequency welding being preferred.

As an alternative or in addition to welding, an adhesive may be applied to the container element prior to attaching the container element to the container body.

Fig. 7 shows a positioning unit 27 according to the invention. The positioning unit may for example be one of the positioning units 27 of the attachment unit 5 shown in fig. 4 and 5. Fig. 7 further illustrates the sealing disk 127 in the process of being placed in the container body 103. As can be taken from fig. 7, the cross section of the sealing disk 127 is larger than the inner cross section of the container body 103. When placed in the container body 103, the edge portion 133 of the sealing disc 127 will fold upwards so that it conforms to the interior of the container wall 105. See also fig. 3. The illustrated sealing disc 127 is a flexible or at least foldable member, such as a laminate of plastic film and aluminum foil, plastic film, paper sheet, paper/plastic laminate, or the like. Alternatively, the container element, such as the internal sealing disk and the bottom disk, may be preformed with sealable edge portions extending perpendicular to the major plane of the container element. In this case, the edge portion is not folded when the container element is inserted into the container body.

The sealing disc 127 is arranged as a shipping seal inside the lid at the open end of the packaging container and is arranged to be removed completely or partially by the user in order to gain access to the package contents in the container. To this end, the sealing disc 127 may be provided with means for facilitating removal, such as a pull tab, tear strip, or the like.

The positioning unit 27 comprises a base plate 49 comprising or consisting of a rigid material, such as a metal or a composite material, and a plunger skirt 51 comprising an elastically deformable material, such as rubber or plastic. Plunger skirt 51 is positioned on top of base plate 49 such that it at least partially covers an upper surface 54 of base plate 49, which upper surface 54 is opposite a lower footprint surface 53 of base plate 49.

The footprint surface 53 is configured to face the container element, here the sealing disc 127, when the container element is applied in the container body 103. The footprint surface 53 of the baseplate 49 has a circumferential edge 55, which in the illustrated example has a substantially polygonal shape. However, it should be understood that the footprint surface may have any other suitable shape that is suitable for the cross-sectional shape of the packaging container to be produced. In the illustrated example, the substantially polygonal shape is a substantially square shape, comprising four

side edge portions

55a, 55b, 55c, 55d, which are connected by outwardly

rounded corner portions

57a, 57b, 57c, 57 d. See fig. 8. In the illustrated embodiment, each

side edge portion

55a, 55b, 55c, 55d includes an inwardly

curved section

59a, 59b, 59c, 59 d. As shown in fig. 8 at the side edge portion 55b having the inwardly curved section 59b, the curved section deviates from the straight line that an ideal polygon would have. The

corner portions

57a, 57b, 57c, 57d are rounded to conform to the contours of the container body 103 that has been made by bending paperboard web material into a tubular shape. The circumferential edge 55 of the footprint surface 53 of the base plate 49 with curved sections deviates from the cross-sectional shape (footprint) of the produced packaging container at one or more curved sections of the circumferential edge 55 of the footprint surface 53. In a corresponding prior art positioning unit as shown in fig. 9, the base plate 49 has the same footprint as the container body 103, with straight side edge portions between the curved corner portions.

In some cases, it is sufficient that only one side comprises a curved section. As shown in fig. 7, when only a single curved section is disposed at the circumferential edge 55 of the footprint surface 53 of the base plate 49, the curved section is preferably positioned at a position corresponding to the connection 106 in the container body 103. The container body 103 is formed by bending a cardboard web material into a tubular shape and the connecting portion is created by longitudinally closing the tube by connecting overlapping or abutting side edges of the sheets. The connection between the side edges may be covered by a sealing strip. As shown in fig. 12a, the connecting portions 106 locally thicken the walls of the container panel and also constitute bending lines where the container walls tend to bend inwardly towards the interior of the container panel. Due to the provision of the curved section in the side edge portion of the circumferential edge of the footprint surface of the substrate, the substrate may pass such a possibly inwardly curved connection 106 without causing damage thereto when the positioning unit 27 inserts the container element 127 into the container body 103 to the desired attachment position in the container body 103.

However, by having both sides with corresponding curved sections, the positioning unit 27 can be turned 180 degrees to even out the wear. When the positioning unit 27 has a substantially square shape, it is advantageous that four equal side edge portions have respective curved sections so that the positioning unit 27 can be turned in steps of 90 degrees. Furthermore, by means of the

curved sections

59a, 59b, 59c, 59d, the risk of damaging other parts of the container wall 105 than the connection can be greatly reduced or avoided.

The

curved sections

59a, 59b, 59C, 59d are located towards the center C of the footprint surface 53₁Is bent inward in the direction of (a). Thus, from a circumferential edge 55 of footprint surface 53 of substrate 49 to a center C of footprint surface 53₁Minimum distance d of_rLess than the distance for a corresponding footprint surface 53 having a generally polygonal shape with straight side edge portions. The ideal straight side edge portion is marked with a dotted line at the side edge portion 55b of the bottom of fig. 8, and goes from the theoretically ideal straight side edge portion to the center C of the footprint surface 53 of the substrate 49₁Having a minimum distance d_iWherein d is_iGreater than d_rFor example at least 1mm larger, such as at least 2mm larger, at least 4mm larger or at least 8mm larger.

The plunger skirt 51 is transitionable between a non-expanded state (see fig. 10) and an expanded state (see fig. 11) by relative movement with respect to the base plate 49. Fig. 10 and 11 show the outer circumference 61 of the plunger skirt 51.

In the non-expanded state of the plunger skirt 51, the shape of the outer contour of the plunger skirt 51 as shown in fig. 10 corresponds to the shape of the base plate 49 shown in fig. 8. Thus, in the non-expanded state, the plunger skirt 51 has the same substantially polygonal shape (footprint) as the base plate 49.

As shown in fig. 12a, when viewed relative to base plate 49, outer circumference 61 of plunger skirt 51 is located at circumferential edge 55 of base plate 49, such as within 3mm from circumferential edge 55 of footprint surface 53 of base plate 49, within 2mm from circumferential edge 55 of footprint surface of base plate 49, or within 1mm from circumferential edge 55 of footprint surface 53 of base plate 49. Preferably, as shown in fig. 10 and 12a, when the plunger skirt 51 is in the non-expanded state, the outer circumference 61 of the plunger skirt 51 coincides with the circumferential edge 55 of the footprint surface 53 of the base plate 49 or is slightly inside the circumferential edge 55 of the footprint surface 53 of the base plate 49. The outer circumference 61 of the plunger skirt 51 has at least one side edge portion including a curved section at a center C toward the outer circumference 61 of the plunger skirt 51 corresponding to the shape of the circumferential edge 55 of the footprint surface 53 of the base plate 49₂Is curved in the direction of (a). In the embodiment shown, there are four

sides

63a, 63b, 63c, 63d, each having a respective

curved section

65a, 65b, 65c, 65 d. The plunger skirt 51 further includes four rounded

corner portions

67a, 67b, 67c, 67d corresponding to the

corner portions

57a, 57b, 57c, 57d of the base plate 49. As shown in fig. 10, in the non-expanded state, from the outer circumference 61 of the plunger skirt 51 to the center C of the polygonal shape₂There is a minimum distance d_o。

In the expanded state, see fig. 11, 12b and 13b, the cross-section (footprint) defined by the outer circumference 61 of the plunger skirt 51 is larger than the cross-section in the non-expanded state of the plunger skirt 51. The outer circumference 61 of the plunger skirt 51 is shown in phantom in fig. 10. In the expanded state, from the outer circumference 61 of the plunger skirt 51 to the center C of the footprint of the plunger skirt 51₂There is a minimum distance d_eThe minimum distance is larger than the minimum distance d in the non-expanded state_oAt least 1mm larger, such as at least 2mm larger, at least 4mm larger or at least 8mm larger. Thus, the bending of the bending section is smaller in the expanded state than in the non-expanded state of the plunger skirt 51. Preferably, the bending is eliminated in the expanded state, so that the

side edge portions

63a, 63b, 63c, 63d form straight lines, or even so that they are given a slight outward bend.

During the transition to the expanded state, pressure is applied to the plunger skirt 51 from above in a manner explained below. Thus, the geometry of the plunger skirt 51 will tend to straighten its

curved sections

65a, 65b, 65c, 65 d. Thus, by careful selection of the shape and material properties of the plunger skirt 51, the desired shape change during the transition may be obtained.

In the expanded state as shown in fig. 11, 12b and 13b, the outer circumference 61 of the plunger skirt 51 is at least partially outside the circumferential edge 51 of the base plate 49. Referring to fig. 13b, there is shown the use of a container element exemplified by a sealing disc 127. In this state, the plunger skirt 51 expands radially from the position shown in fig. 13a until the outer circumference of the plunger skirt 51 reaches the outside of the circumferential edge 55 of the footprint surface 53 of the baseplate 49. As shown in fig. 13b, the plunger skirt then contacts the edge portion 133 of the sealing disk 127 and presses the edge portion 133 of the sealing disk 127 against the interior of the container wall 105. If the above-described retaining elements 34 are used in the transport plate 29, the plunger skirt 51 may contribute to pressing the container element back in the radial direction in case the container element itself cannot rebound sufficiently.

Returning again to fig. 7, it can be seen that there is a first piston 71 and a second piston 73 coaxial with the first piston 71. Referring to fig. 4 and 5, the

pistons

71, 73 extend in an axial direction a coinciding with the vertical direction z of the attachment unit 5. The base plate 49 is attached to an end portion of the first piston 71 such that the footprint surface 53 is perpendicular to the axial direction a. The plunger skirt 51 is attached to the end portion of the second piston 73. The first piston 71 and the second piston 73 are configured to be axially displaceable in synchronism with each other and independently of each other.

Upon displacement of the positioning unit 27 to a pre-selectable attachment position of the container element 127, the plunger skirt 51 remains in the non-expanded state. See fig. 12 a. When the container element 127 has reached the pre-selectable attachment position and the plunger skirt 51 is pressed in the radial direction against the rim portion of the container element 127, the plunger skirt 51 transforms into an expanded state as shown in fig. 12 b. Accordingly, the tip end portion of the second piston 73 is moved closer to the tip end portion of the first piston 71, thereby pressing the plunger skirt 51 outward. Such relative movement between the pistons in the axial direction a may be in the range 1mm to 15mm, preferably 3mm to 10 mm.

Referring to fig. 13a and 13b, the plunger skirt 51 is transferred to an expanded state by means of a relative displacement between the first piston 71 and the second piston 72, wherein the end portion 78 of the second piston 72 moves closer to the end portion 77 of the first piston 71. When the outer ends 77, 78 of the first and second pistons 71, 72 are brought together in this manner, the end portion 78 of the second piston 72, which is attached to the plunger skirt 51, for example by fusion or adhesion, moves towards the base plate 49 and applies pressure to the plunger skirt 51 between the end portion 78 of the second piston 72 and the base plate 49. Pressure on the elastically deformable plunger skirt 51 causes the plunger skirt 51 to decrease in size in the axial direction a, while the outer circumference 61 of the plunger skirt 51 expands outwardly in the radial direction R by sliding on the upper surface 54 of the base plate 49 opposite the footprint surface 53. Thus, the shape of the plunger skirt 51 changes under the influence of the compressive force acting in the axial direction a between the tip end portion 78 of the second piston 72 and the base plate 49 at the tip end portion 77 of the first piston 71.

In the expanded state of the plunger skirt 51 as shown in fig. 13b, the edge portion of the outer circumference of the plunger skirt 51 contacts the edge portion of the container element inserted into the container and exerts a pressure on this edge portion so that it is pressed against the inside of the container wall. In the example of fig. 13a and 13b, the container element is illustrated by a sealing disc 127 with an upwardly folded edge portion 133. It should be understood that the positioning unit may be used to insert and position any container element as disclosed herein, including a tray, a rim or a pre-formed tray or sealing disc.

The outer circumference of the plunger skirt presses the container element against the inside of the container wall of the container body 103 placed in the positioning chamber. The edge portion of the outer circumference of the plunger skirt 51, which is arranged to be in contact with and to exert pressure on the container element in the non-expanded state of the plunger skirt 51, may have a contact surface which is slightly inclined with respect to the vertical direction of the positioning unit in the non-expanded state of the plunger skirt.

When pressure is applied to the plunger skirt 51 to change the shape of the plunger skirt 51 from the non-expanded state to the expanded state, the

corner portions

67a, 67b, 67c, 67d of the plunger skirt 51 generally move outwardly a shorter distance than the

sides

63a, 63b, 63c, 63d between the

corner portions

67a, 67b, 67c, 67 d. By way of example, when the

side portions

63a, 63b, 63c, 63d move outwardly by about 4mm, the

corner portions

67a, 67b, 67c, 67d may only move outwardly by half that distance, i.e., by about 2 mm.

In order to further improve the contact of the container element with the container body material in the corner portions, thickened corner portions may be arranged on the upper surface of the base plate, i.e. on the surface opposite to the footprint surface of the base plate. The thickened corner portions forming raised areas on the upper surface of the base plate serve to force the plunger skirt further out, thereby exerting increased pressure on the applied container element and improving contact between the container element and the container body. Thereby, the connection formed between the container element and the corner portion of the container body may be improved. In particular, increased pressure in the corner portions of the container body may assist in forming a tight seal between the container body material and the sheet-like container element. When the container element is folded and aligned with the container body wall, excess material present at the corner portions of the sheet-like container element (such as the floor pan or sealing disc) will typically wrinkle at the corners of the container. In this case, the increased pressure generated at the corner portions of the container body will compress the corrugations and will help to form a good functional bond, such as a heat weld between the container body material and the sheets in the container element. When a thermal welding process is used in order to bond the container element to the wall of the container body, at least one and preferably both of the container element and the container wall comprise a sufficient amount of thermoplastic material to create a functional bond. As described herein, the bonding of the container element to the container body may alternatively be performed by means of an adhesive or by a combination of welding and adhesive.

The retaining means may comprise a liner (not shown) located in the positioning chamber and arranged to shield an exposed edge of the container body. The lining is preferably applied such that it surrounds the positioning cavity, thereby locally reducing the cross-section of the positioning cavity. The thickness of the liner may be the same as the thickness of the sheet material used for the container body, and may be in the range of 0.2mm to 2mm, such as 0.5mm to 1.5mm or 0.6mm to 0.9 mm. This will for example be helpful when folding the edge portions of the sealing disc or the bottom plate.

The method of positioning the

container elements

115, 117, 121, 123, 127 in the container body 103 by means of the positioning unit as described herein may comprise

The container element is moved to a pre-selectable position in the container body 103 by means of the positioning unit 27 inserting the container element into the container body 103, the plunger skirt 51 thereby being in a non-expanded state,

-transforming the plunger skirt 51 into an expanded state when the container element reaches a pre-selectable position, thereby pressing the

rim portion

116, 129, 131, 135 of the container element in a direction towards the inner wall of the container body 103.

As described above, the step of transitioning plunger skirt 51 to the expanded state may be performed by means of a relative displacement between first piston 71 and second piston 73, wherein a tip portion of second piston 73 moves closer to a tip portion of first piston 72, as disclosed herein.

The method may further comprise

Fixing the

container elements

115, 117, 121, 123, 127 to the container body 103, for example by means of welding and/or adhesive

If the attachment unit 5 comprises a transmission plate 29, the method may comprise

Placing the

container elements

115, 117, 121, 123, 127 in the transfer chamber 33,

displacing the transmission plate 29 to the second position,

displacing container elements from the transfer chamber 33 in the transfer plate 29 into the container body 103 by means of the positioning unit 27 by moving through the transfer chamber 33 and at least partly through the positioning chamber 37 of the holding device 23.

If the attachment unit 5 comprises a plurality of positioning units 27, the method may comprise: a plurality of

container elements

115, 117, 121, 123, 127 are positioned simultaneously into the respective container bodies 103 by the positioning unit 27.

The container elements can be placed in the transport chamber 33 of the transport plate 29 by means of an optional container element supply 41 comprising at least one gripper unit 42. A stack of container components (e.g., bottom rim 117) may be stored in the cassette 43. The number of stacks in the cassette 43 and the number of gripper units 42 corresponds to the number of transport chambers 33 in the transport plate 29, in the case shown four stacks. The gripping unit 42 is capable of gripping individual container elements, here bottom grommets 117, moving the individual container elements from the openings 45 in the magazine 43 and placing the individual container elements in the corresponding transfer chambers 33. As an example, four individual container elements are clamped simultaneously. The clamping unit 42 comprises four

clamping members

44a, 44b, 44c, 44d clamped at the corners of the container element. The positions of the

clamping members

44a, 44b, 44c, 44d correspond to the positions of the notches 36 of the transmission plate 29. As mentioned above,

such clamping members

44a, 44b, 44c, 44d and their corresponding recesses 36 are particularly useful when the container element is not a sheet-like element such as a bottom disc or sealing disc but is formed as a ring, such as a backing ring.

As an option, the attachment unit 5 may include an inner housing 47, as shown by the dotted lines in fig. 4 and 5. The inner housing 47 is located inside the outer housing 7 and is arranged above the positioning chamber 37 of the holding device 23 to provide an additional protective atmosphere.

Further modifications of the invention are possible within the scope of the appended claims. Therefore, the present invention should not be considered as being limited by the embodiments and the drawings described herein. Rather, the full scope of the invention should be determined by reference to the specification and drawings, which are appended to the claims.

Claims

1. A positioning unit (27) for positioning a container element (115, 117, 121, 123, 127) in a container body (103),

the positioning unit (27) comprises:

-a substrate (49) comprising or consisting of a rigid material, and

-an elastically deformable plunger skirt (51),

the base plate (49) having a footprint surface (53) with a circumferential edge (55) comprising a plurality of side edge portions (55a, 55b, 55c, 55d) connected by corner portions (57a, 57b, 57c, 57d),

the plunger skirt (51) covering a surface (54) of the base plate (49) opposite the footprint surface (53),

it is characterized in that the preparation method is characterized in that,

at least one of the side edge portions (55a, 55b, 55c, 55d) of the peripheral edge (55) of the base plate (49) comprises a curved section (59a, 59b, 59c, 59d) that curves in an inward direction from the peripheral edge (55) of the footprint surface (53),

the plunger skirt (51) being transitionable between a non-expanded state and an expanded state,

the plunger skirt (51) having an outer circumference (61) which in the non-expanded state is located at the circumferential edge (55) of the footprint surface (53) of the baseplate (49) and which in the expanded state is located at least partially outside the circumferential edge (55) of the footprint surface (53) of the baseplate (49),

the outer circumference (61) of the plunger skirt (51) in the non-expanded state has a shape in which at least one side (63a, 63b, 63c, 63d) of the outer circumference (61) of the plunger skirt (51) comprises a curved section (65a, 65b, 65c, 65d), wherein the curved section (65a, 65b, 65c, 65d) is curved in an inward direction from the outer circumference (61) of the plunger skirt (51), the positioning unit (27) further comprising a first piston (71) and a second piston (73), the first piston (71) and the second piston (73) extending in an axial direction (A), wherein the second piston (73) is coaxial with the first piston (71),

the base plate (49) being connected to an end portion of the first piston (71) such that the footprint surface (53) of the base plate (49) is perpendicular to the axial direction (A),

the plunger skirt (51) being connected to an end portion of the second piston (73),

the first and second pistons (71, 73) are configured to be axially displaceable in synchronism with each other and independently of each other, and wherein the distal end portion of the second piston (73) is configured to be closer to the distal end portion of the first piston (71) than to the non-expanded state when the plunger skirt (51) is in the expanded state.

2. The positioning unit (27) as claimed in claim 1, wherein the outer circumference (61) of the plunger skirt (51) in the non-expanded state has a shape corresponding to the shape of the circumferential edge (55) of the footprint surface (53).

3. The positioning unit (27) as claimed in claim 1, wherein at least two of the plurality of side edge portions (55a, 55b, 55c, 55d) of the circumferential edge (55) of the footprint surface (53) of the substrate (49) comprise respective curved sections (59a, 59b, 59c, 59 d).

4. The positioning unit (27) as claimed in claim 3, wherein each of the side edge portions (55a, 55b, 55c, 55d) of the footprint surface (53) of the substrate (49) comprises a respective curved section (59a, 59b, 59c, 59 d).

5. The positioning unit (27) as claimed in claim 1, wherein in the expanded state of the plunger skirt (51) the bending of the bending sections (65a, 65b, 65c, 65d) of the sides (63a, 63b, 63c, 63d) of the outer circumference (61) of the plunger skirt (51) is changed such that in the expanded state of the plunger skirt (51) the bending sections (65a, 65b, 65c, 65d) of the sides (63a, 63b, 63c, 63d) of the outer circumference (61) of the plunger skirt (51) are less bent in the inward direction or in the expanded state of the plunger skirt (51) the bending sections (65a, 65b, 65c, 65d) of the sides (63a, 63b, 63c, 63d) of the outer circumference (61) of the plunger skirt (51) are less bent in the inward direction, 65b, 65c, 65d) is straight or, in the expanded state of the plunger skirt (51), the curved section (65a, 65b, 65c, 65d) of the side portion (63a, 63b, 63c, 63d) of the outer circumference (61) of the plunger skirt (51) is curved in an outward direction.

6. The positioning unit (27) as claimed in claim 1, wherein the curved section (59a, 59b, 59c, 59d) of the side edge portion (55a, 55b, 55c, 55d) of the circumferential edge (55) of the footprint surface (53) of the base plate (49) extends from a corner portion (57a, 57b, 57c, 57d) to an adjacent corner portion (57a, 57b, 57c, 57d) of the circumferential edge (55) of the footprint surface (53) of the base plate (49).

7. The positioning unit (27) as set forth in claim 1, wherein the outer circumference (61) of the plunger skirt (51) has a polygonal shape from the outer circumference (61) of the plunger skirt (51) to a center (C) of the polygonal shape of the plunger skirt (51) in the expanded state₂) Minimum distance (d)_e) Is larger than from the outer circumference (61) to the center (C) of the plunger skirt (51) in the non-expanded state₂) Minimum distance (d)_o)。

8. The positioning unit (27) as set forth in claim 7, wherein in the expanded state from the outer circumference (61) of the plunger skirt (51) to a center (C) of the polygonal shape of the plunger skirt (51)₂) Minimum distance (d)_e) From the outer circumference (61) to the center of the plunger skirt (51) in the non-expanded state(C₂) Minimum distance (d)_o) At least 1mm larger.

9. The positioning unit (27) as set forth in claim 8, wherein in the expanded state from the outer circumference (61) of the plunger skirt (51) to a center (C) of the polygonal shape of the plunger skirt (51)₂) Minimum distance (d)_e) From the outer circumference (61) to the center (C) of the plunger skirt (51) in the non-expanded state₂) Minimum distance (d)_o) At least 4mm larger.

10. The positioning unit (27) as claimed in any one of the preceding claims, the base plate (49) having an extension in a height direction (z) perpendicular to the footprint surface (53), wherein the extension in the height direction (z) is larger at a corner portion (57a, 57b, 57c, 57d) than at an adjacent curved section (59a, 59b, 59c, 59d) of the at least one side edge portion (55a, 55b, 55c, 55 d).

11. An attachment unit (5) for attaching a container element (115, 117, 121, 123, 127) to a container body (103), the attachment unit (5) comprising:

-holding means (23) adapted to hold the container body (103) when attaching the container element (115, 117, 121, 123, 127) to the container body (103),

-a positioning unit (27) according to any of the preceding claims,

said holding means (23) comprising at least one through-going positioning cavity (37) adapted to receive a portion of said container body (103),

the positioning unit (27) is aligned with the positioning cavity (37) such that the container element (115, 117, 121, 123, 127) can be displaced into the container body (103) by means of the positioning unit (27) by moving the container element (115, 117, 121, 123, 127) at least partially through the positioning cavity (37) of the holding device (23).

12. Attachment unit (5) according to claim 11, wherein the retaining means (23) comprise a lining in the positioning cavity (37) so as to locally reduce the cross section of the positioning cavity (37).

13. The attachment unit (5) according to claim 12, wherein the inner lining has a thickness in the range of 0.2mm to 2 mm.

14. The attachment unit (5) according to claim 13, wherein the inner lining has a thickness in the range of 0.5mm to 1.5 mm.

15. Attachment unit (5) according to claim 11, wherein the holding device (23) comprises a welding unit (39) arranged around the positioning cavity (37), the welding unit (39) being adapted to weld the container element (115, 117, 121, 123, 127) to the container body (103), the welding unit (39) comprising a coil extending around the positioning cavity (37).

16. Attachment unit (5) according to claim 11, wherein the attachment unit (5) further comprises a transport plate (29) for transporting the container elements (115, 117, 121, 123, 127) between a first position and a second position,

the transfer plate (29) comprising at least one through-going transfer cavity (33) adapted to receive and hold the container elements (115, 117, 121, 123, 127),

the transfer plate (29) being displaceable between the first position, in which the transfer plate (29) is adapted to accommodate the container elements (115, 117, 121, 123, 127) in the transfer cavity (33), and the second position, in which the transfer cavity (33) is aligned with the positioning cavity (37) of the holding device (23),

the transport plate (29) in the second position is located between the positioning unit (27) and the positioning cavity (37) of the holding device (23) such that the container elements (115, 117, 121, 123, 127) can be displaced from the transport cavity (33) in the transport plate (29) into the container body (103) by means of the positioning unit (27) by moving the container elements (115, 117, 121, 123, 127) through the transport cavity (33) and at least partially through the positioning cavity (37) of the holding device (23).

17. Attachment unit (5) according to claim 16, wherein the through transmission cavity (33) of the transmission plate (29) has a smaller cross section (a) than the positioning cavity (37) of the holding device (23)₁)。

18. Attachment unit (5) according to claim 16, wherein the transfer plate (29) comprises one or more holding elements (34) adapted to hold the container elements (115, 117, 121, 123, 127) in the transfer cavity (33), the holding elements (34) being located at a wall of the transfer cavity (33).

19. Attachment unit (5) according to claim 18, wherein the retaining element (34) is located at the centre of the side of the wall.

20. Attachment unit (5) according to any one of claims 11 to 19, wherein the retaining means (23) comprise a plurality of positioning cavities (37) and the attachment unit (5) comprises a plurality of positioning units (27) according to any one of claims 1 to 10 aligned with the positioning cavities (37), so that each positioning unit (27) is associated with a respective positioning cavity (37).

21. Attachment unit (5) according to claim 20, wherein the positioning cavity (37) and the positioning unit (27) are arranged in a row.

22. Attachment unit (5) according to claim 20, wherein the plurality of positioning units (27) are adapted to simultaneously position a plurality of container elements (115, 117, 121, 123, 127) in the respective container bodies (103).

23. An apparatus (1) for attaching a container element (115, 117, 121, 123, 127) to a container body (103) in a flow of a container (101), the apparatus (1) comprising:

-a transport device (3) configured to transport a flow of the containers (101) through the apparatus (1),

-at least one attachment unit (5) according to any one of claims 12 to 22, arranged along the transport device (3).

24. A method of positioning a container element (115, 117, 121, 123, 127) in a container body (103) by means of a positioning unit (27) according to any one of claims 1 to 10, the method comprising:

-moving the container element (115, 117, 121, 123, 127) in the axial direction (A) to a pre-selectable position within the container body (103) by means of the positioning unit (27) with the plunger skirt (51) in the non-expanded state,

-transforming the plunger skirt (51) into the expanded state when the container element (115, 117, 121, 123, 127) reaches the pre-selectable position, thereby pressing an edge portion (116, 129, 131, 135, 137) of the container element (115, 117, 121, 123, 127) in a direction towards an inner wall of the container body (103), wherein transforming the plunger skirt (51) into the expanded state is performed by means of a relative displacement between the first piston (71) and the second piston (73), wherein during the transformation from the non-expanded state into the expanded state the end portion of the second piston (73) moves closer to the end portion of the first piston (71).

25. The method of claim 24, further comprising:

-fixing the container element (115, 117, 121, 123, 127) to the container body (103) by means of welding and/or adhesive.

26. The method according to claim 24, when performed by an attachment unit (5) according to any one of claims 16 to 19,

-placing the container elements (115, 117, 121, 123, 127) in the transfer chamber (33),

-displacing the transmission plate (29) to the second position,

-displacing the container elements (115, 117, 121, 123, 127) from the transfer cavities (33) in the transfer plate (29) into the container body (103) by means of the positioning unit (27) by moving through the transfer cavities (33) and at least partly through the positioning cavities (37) of the holding device (23).

27. Method according to any one of claims 24 to 26, performed by means of an attachment unit (5) according to any one of claims 20 to 22, wherein a plurality of said container elements (115, 117, 121, 123, 127) are positioned simultaneously into the respective container bodies (103) by means of said positioning unit (27).